Petroleum is currently the primary chemical feedstock for the production of polymers. This commodity is becoming more expensive, impacting the cost of plastic materials and ultimately end-products. Petroleum is a non-sustainable material and is subject to geopolitical and environmental forces that further impact cost and future availability. Therefore, an alternative source of chemical feedstock for the production of polymers is desirable, one that is not subject to geopolitical and environmental influences that impact availability, price, and the environment.
Feathers, such as poultry feathers, composed of approximately 90% keratin, are a plentiful and readily-available byproduct in the food processing industry, with most of the material being disposed of as waste. Previous documented efforts using poultry feathers as a chemical feedstock have used water-based or other solvent-based techniques. In one instance chicken feathers were dispersed in water prior to polymerization (Graft Polymerization of Native Chicken Feathers for Thermoplastic Applications, Enqi Jin, et al, J. Agric. Food Chem. 2011, 59, 1729-1738). In other instances the feathers were degraded with harsh chemicals and then used as a substrate for further polymerizations (U.S. Pat. No. 3,642,498 “Keratin protein product and process of preparing same”). Regardless, in all cases, at the completion of the reaction, the water, solvents or other chemicals needed to be removed. Other art includes treating natural keratin with OH containing plasticizer allowing the protein to be pressed into films at typical polymer processing temperatures (Composition and Films Comprised of Avian Feather Keratin, U.S. Pat. No. 7,066,995 B1).
Other documented efforts include the use of bi-functional thiols, such as β-mercaptoethanol, to break the disulfide bonds found in feathers, keratin and other materials containing disulfide bonds, for the purpose of extracting the keratin.